books.google.com - Offering a solid introduction to the entire modeling process, A FIRST COURSE IN MATHEMATICAL MODELING, 4th Edition delivers an excellent balance of theory and practice, giving students hands-on experience developing and sharpening their skills in the modeling process. Throughout the book, students practice...https://books.google.com/books/about/A_First_Course_in_Mathematical_Modeling.html?hl=hu&id=XPxrItVsXpQC&q=assume&utm_source=gb-gplus-shareA First Course in Mathematical Modeling